Share Bucket (free) enables you to annotate and upload screen captures. While it may not be the most original idea on the Mac App Store, it's certainly a welcome entry to the field. It offers simple, cloud-integrated sharing with a few minor growing pains.
Share Bucket supports Dropbox, Google Drive and SkyDrive. You pick the destination and authenticate.
Menu bar-based options enable you to capture and annotate, or to upload existing images to your account. Once uploaded, the app triggers notification center, so you always know when the material is ready to use. A URL awaits you on the system pasteboard.
A critical "Auto-upload" option in Preferences allows you to automatically shoot and upload. That's perfect for anyone who takes occasional screenshots and wants immediate gratification from a shareable asset.
Share Bucket did experience some issues during my testing. After editing the image you see at the start of this post, here's what it uploaded to Google. Essentially, it failed to include my most recent edit, creating a one-step-out-of-date result.
I would have liked an option to auto-move screenshots to a specific folder after upload, as well as a menu item that enabled me to clean up yesterday's screenshot, last week's screenshots and all screenshots from my Google Drive. The one option it does have, which is quite nice, is an Auto-delete one. You specify the time limit in days (I have it set up for three days), and it removes shared files at least that old.
Another welcome option enables you to automatically downscale images from Retina Macs.
Despite a rather ugly menu bar icon, I like Share Bucket and look forward to giving it a deeper test run over the next few weeks. For a free app, it offers excellent utility.